1. Department of Earth Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK; Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK.
2. Departments of Earth Sciences and Geography, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK.
3. Department of Biology and Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA.
4. Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL 60022, USA.
5. Department of Earth and Environmental Sciences and Museum of Paleontology, University of Michigan, Ann Arbor, MI 48109, USA.
6. Department of Earth Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK.
7. Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK.
8. Imaging and Analysis Centre, Natural History Museum, London, SW7 5BD, UK.